Wellness “wearables” have become an integral part of many Americans’ wardrobes, providing feedback and metrics to help you meet your health goals. In fact, 2020 data from the Pew Research Center suggested at least 20% of Americans use a fitness tracking device to enhance their physical performance—and that was before the pandemic made health a bigger lifestyle focus for many.

Now a new study released by a team of scientists at Notre Dame University suggests that despite this intention, wearing such devices could actually pose some health risk.

The research, led by a team of biochemists and astrophysicists and published in December 2024 in the journal Environmental Science and Technology Letters, explains that many watch bands used in wearable fitness devices contain what the researchers referred to as fluoroelastomers. This type of synthetic rubber is often utilized due to its resistance to skin oils, sweat, and extreme temperatures, but these scientists say it is ultimately considered a form of per- and polyfluoroalkyl substances (PFAS)—also known as toxic “forever chemicals.”

To understand the scope of the problem, the researchers analyzed 22 watch bands across a range of brands and price points. First, they screened the items for fluorine, a chemical element suggestive of widespread use of fluoroelastomers in the products’ manufacturing. Next, they looked for 20 different types of PFAS, PFAS precursors, and PFAS byproducts, and identified that PFHxA, a breakdown chemical resulting from other PFAS, was the most widely present across brands. “The very high concentrations of PFHxA readily extractable from the surfaces of fluoroelastomer watch bands, together with the current limited knowledge on the dermal absorption of PFHxA, demonstrate the need for more comprehensive exposure studies of PFHxA,” the researchers concluded.

PFAS can be found in many places, including in our drinking water, soil, food, food packaging, cleaning products, personal care products, manufacturing plants, and more. Past research, including a June 2024 study published in the journal Environment International, has established that in addition to being consumed or inhaled, PFAS can also enter the bloodstream when they come into contact with skin. Though the use of PFAS has declined over the past 25 years, virtually all Americans have some level of PFAS in their bloodstream, national data shows.

According to the Environmental Protection Agency (EPA), exposure to high levels of PFAS may cause a range of health problems including but not limited to:

  • Reproductive effects such as decreased fertility or increased high blood pressure in pregnant women
  • Developmental effects or delays in children, including low birth weight, accelerated puberty, bone variations, or behavioral changes
  • Increased risk of some cancers, including prostate, kidney, and testicular cancers
  • Reduced ability of the body’s immune system to fight infections, including reduced vaccine response
  • Interference with the body’s natural hormones
  • Increased cholesterol levels and/or risk of obesity

The good news? Most brands of wearable wellness accessories allow you to swap out the bands for the materials of your choosing. Silicone, leather, metal, and fabric straps can all serve as safer alternatives—just be sure to check the label for signs that the product is PFAS-free.

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Author
Lauren Gray
Lauren has spent more than 10 years of experience covering health and wellness for SELF Magazine, Popular Mechanics, Yahoo! News, MSN, Best Life, and more. For three years she led the writing center at Woodstock School, one of the oldest international boarding schools in India.  Lauren is young adult breast cancer survivor who now centers her per...
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Lauren Gray